Feather edger



July 30, 1957 w. s. BRUcKl-:R 2,800,751

- FEATHER EDGER Filed April 4, 1956 INVENTR. WILL/AM S. BRUCKER BY TS aw. .kwh .Q -L XJ United States Patent iO FEATHER EDGER William S. Brucker, Towson, Md., assignor to The Black & Decker Manufacturing Company, Towson, Md., a corporation of Maryland Application April 4, 1956, Serial No. 576,265

3 Claims. (Cl. 51-197) This invention is directed to improvements in disk type mounting pads for abrasive disks and more particularly to the type known as feather edgers.

Such abrasive disk carriers are usually formed of a cushioning material such as Isponge rubber or the like carried on a stiffer rubber backing cured or cemented to a hub structure attachable to the propelling means such as a spindle of a motor shaft. The abrasive disk usually is held upon the flexible backing by a clamping washer or clamping disk removable in various manners. Such clamping means can involve the element of danger to the operator if of improper construction and the general object of the present invention is the provision of a novel abrasive disk clamping means which cannot be released during the use of the apparatus but which is quickly ren movable.

A more specific object of the present invention is the provision of an abrasive disk clamping means on a feather edger which will hold the abrasive disk at its central region suiciently rmly as to prevent slippage between the abrasive disk and the backing structure regardless of the amount of distortion exerted upon the abrasive disk and backing structure.

A still further object of this invention is the provision of a quick release abrasive disk clamping means which is opposed from release by centrifugal force.

Other objects of the present invention will become apparent to those skilled in the art from the following description referring to the accompanying drawings showing a preferred embodiment thereof. The essential characteristics are summarized in the claims.

In the drawings:

Fig. 1 is a cross sectional view taken through the axis of the disk mounting head showing the abrasive disk locking mechanism in locked position; and

Fig. 2 is a cross sectional view taken along the line 2-2 of Fig. 1.

Referring to the drawings in Fig. l I show a yieldable rubber backing member which is cured or cemented to an internally threaded hub structure 11 having an integral disk formation 12 about which the backing 10 is molded and secured. The backing 10 has a pliable facing or sponge rubber cushion 13 secured thereto of doughnut shape with a core 14 of somewhat lesser thickness and of relatively stiff compressible rubber. The abrasive disk 15 is clamped to this rubber core as will be explained.

The abrasive disk locking means comprises a cup shaped and flanged member 18 the outer ange 18a of which is in diameter approximately equal to the diameter of the relatively stiff rubber core 14 so that the outer ange 18a of the cup will serve to clamp the abrasive disk 15 to core 14.

The cup shaped member 18 has a perforated bottom for the passage therethrough of a headed locking bolt 20 and a compression spring 21 thrusting against the bottom of the cup formation and the head 22 of the bolt tending at all times to urge the bolt outwardly to release the abrasive disk.

j 2,800,751 Patented July 30, 1957 ICC To maintain the bolt 20 in locked position the inner pilot end 24 of the bolt is provided with a detent head which is engaged by a rockable, at detent lever 25 so constructed as to remain in locking engagement with the bolt through the iniuence of centrifugal force and through the split band spring26 disposed in an external dat groove 27 formed in the hub structure 11. The lever is disposed in a narrow groove 23 formed centrally of the shallow groove 27.

As shown in Fig. 2 the rocker lever 25 has an inner detent end 30 passing through a radial opening 33 in the hub structure and engaging the shoulder 24 formed on the inner end of the bolt 20. The lever 25 is disposed in a narrow groove 2.3 with a fulcrum portion 31 resting on the bottom of the groove 23. A split cylindrical ring or C-shaped spring 26 bears upon part of the top of the lever adjacent its detent end normally to urge the detent portion 30 of the lever inwardly. The spring has a rectangular opening 36 formed therein through which the outer manually operated end 32 of the lever extend-s. When lever end 32 is depressed manually the bolt 20 is released and spring 21 has a pop out action on the. bolt and cup thus releasing the abrasive disk.

The mass of the lever 25 to the right of the fulcrum formation 31 as viewed in Fig. 2 is greater than the mass of the detent side of the lever so that upon rotation of the head at feather edging speeds the detent is maintained in an inward position in engagement with the shoulder 24 of the bolt 20.

In applying the abrasive disk the same is placed over the cup, spring and bolt structure and the bolt head is pressed inwardly with the pilot end camming transversely against the detent end 30 of the lever 25 until the detent end snaps behind the shoulder 24 of the bolt. When desiring to remove the worn abrasive disk the manual portion of the lever 32 is depressed and the reaction of the released spring 21 causes the cup, bolt and spring to pop outwardly thus facilitating removal of the worn disk.

While the device herein has been referred to as a feather edger it will be understood by those skilled in the art that the apparatus can be used for sanding, grinding and polishing as desired.

I claim:

l. A support and driving means for an abrasive disk comprising a hub structure adapted to be attached to a driving spindle, an abrasive disk back-up structure on the hub structure, a cup shaped abrasive disk clamping member, a helical spring in the cup of said member, a securing bolt extending through the cup shaped member axially inwardly into the central portion of the hub and urged outwardly by the spring while the spring exerts inward pressure on the cup shaped member, a detent lever carried by the hub structure at the rear of said back-up structure in a radial external groove formed in the hub structure and extending over at least a portion of the periphery thereof, said lever having a portion extending radially inwardly to engage said bolt against axial movement and also having an end portion accessible for external force application in releasing the bolt, and a split ring spring carried by the hub structure and bearing upon 'said lever to maintain the lever in detent engagement with the bolt.

2. A support and driving means for an abrasive disk comprising a hub structure adapted to be attached to a driving spindle, a disk back up structure comprising a back secured tothe hub structure, a pliable rubber facing comprising an abrasive disk support secured to the rubber back to flexibly support an abrasive disk, a resilient core member forming a hub-like structure reacting on the rubber back and adapted to support an inner perimeter of an abrasive disk, a flanged cup shaped member received in a central opening of the core member and having an outer ange overlying the outer face of the rubber core, a helical spring in the cup of said member, a securing bolt extending through the cup shaped member axially inwardly into the central portion of the hub `and urged outwardly by the spring while the spring exerts inward pressure on the flanged cup shaped member, a detent lever carried by the hub `structure at the reartof said back in a radial external groove formed in the hub structure and extending over at least a portion of the periphery thereof, said lever having a detent projection engageable with said bolt to retain the same against a force of said helical spring and having a portion accessible from the exterior of the hub for manual application of a bolt releasing force thereto, and a split ring spring carried by the hub structure and bearing upon said lever to mainv tain the lever in detent engagement with the bolt.

3. A support and driving means for an abrasive disk comprising a hub structure adapted to be attached to a driving spindle, an abrasive disk back up structure comprising a rubber back secured to the hub structure, a sponge rubber facing comprising an abrasive disk support secured to the rubber-back to exibly support an abrasive disk, a resilient core member forming a hub-like structure of the sponge rubber of less resiliency and thickness than the sponge rubber facing, a anged cup shaped member with cup portion received in a central opening of the core member and anged portion thereof overlying the end of said core, a helical spring in the cup of said member, a securing bolt extending through the cup shaped member axially inwardly into the central portion of the hub and urged outwardly by the spring While the spring exerts inward pressure on the flanged cup shaped member, a detent lever carried by the hub structure at the rear of said rubber back in a radial groove formed in the hub structure and extending over at least a portion of the periphery thereof, said lever being engageable with said bolt to retain the same against an axial force applied by said helical spring and also being externally manually operable to release said bolt, and a split cylindrical type ring spring carried by the hub structure and bearing upon said lever to maintain the lever in detent engagement with the bolt.

References Cited in the file of this patent UNITED STATES PATENTS 

